Charles Scalliet of Persetel Q Data has won the Ingres Technical Innovation award for the User Friendly Backup program developed for the National Traffic Information System (NaTIS). Ingres is Computer Associates` key database product for the UNIX market. NaTIS is a real-time, distributed, replicated system which stores and maintains the data required to enforce the Road Traffic Act of South Africa. Developed by Persetel Q Data for the Department of Transport, The application is nearing completion, although already deployed throughout the country. "The NaTIS system maintains about 150GB of data," explains Scalliet. "The data is maintained on three levels to ensure redundancy and is distributed amongst 106 database servers. An in-house developed replication mechanism (because Ingres` replication software was not available at the time when development started) is used to distribute the data." The data maintained includes personal information on individuals` and businesses` vehicles and related information, as well as information on accidents, contraventions and financial data. The system is also currently being installed in Namibia. "The UFB program is one of many ideas we implemented in the NaTIS. It is an interactive forms-base "shell" on top of the Ingres checkpointdb and rollforwarddb programs which are used to backup and restore Ingres databases. "A general problem with backing up databases is that some users simply re-use the same tape when instructed to use the next tape. To solve this problem, the UFB labels every tape and checks every tape for proper sequencing. This forces users to properly sequence tapes, as tapes cannot be re-used unless formatted." Normally, he says, a backup command (tar/cpio) is started by checkpointdb for every Ingres location. This is also very ineffective as space is wasted on the many tapes that one subsequently has to use. To solve the problem non-rewinding tapes may be used so that multiple backups can be done on the same tape. "This is very risky as data could be overwritten when the rewinding tape devices are used instead of non-rewinding tape devices. The UFB uses a single backup command to backup the entire database and therefore non-rewinding devices need not be used." The UFB also backs up all the relevant internal Ingres files, such as journal and dump files. While a database is restored or backed up, the user is shown exactly what is being done by the UFB. The current table being restored or backed up is also shown. Furthermore, it is also shown what percentage of the database has been restored or backed up. The current tape sequence is also indicated. All of this information is recorded in detail in system log files for use by system administrators.
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